My idea was to do this with a prefix. Another idea would be to do this with a hash which represents the hierarchial structure of the GUI

You are asking for objects.... an object is essentially a blessed hash, that can contain all sorts of methods and data. So you would have $obj1->{'frame1'}->{'button2'}

But there is an arcane underlying naming convention in Tk, in case you want to use it, for example:

#!/usr/bin/perl
use strict;
use Tk;
use Data::Dumper;

my $mw = MainWindow->new;

for(0..4){
$mw->Button(-text => "Hello World$_",
                     -command=>[\&change])->pack;
}
MainLoop;

sub change {
#Tk dosn't pass it's widget reference in callbacks
#Only the bind() method will implicity pass a widget reference, and ev
+en
#this default (and generally preferred) action can be defeated.
#use $Tk::widget
print "sub-input->@_\n";
my $caller = $Tk::widget;
#print Dumper([$caller]);
print "$caller   ";
print $caller->{'_TkValue_'},'     ';
my $text = $caller->cget('-text');
print "$text\n";
$caller->configure(-text=>"Hello Stranger");
}
[download]

or try this

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = tkinit;

my $id = $mw->id;
print "mainwindow->$id\n";

my $button = $mw->Button(-text =>'Exit',
                         -command =>sub {Tk::exit;}
                        )->pack();

my $buttonid = $button->id;
print "button->$buttonid\n";
            
my $mwpath = $mw->pathname($id);
print "mwpath->$mwpath\n";

my $buttonpath = $button->pathname($buttonid);
print "buttonpath->$buttonpath\n";

MainLoop;
[download]

if you want a simple example of how to make your own package or module, google for "perl tk derived mega", and see my educational example of a simple Tk module example at CanvasDirTree.... you can use it as a template for making your own.